JPS6350711B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention performs development using a dry toner,
The present invention relates to a transfer and fixing device for copying machines, printers, facsimile machines, etc. that performs transfer and fixing on transfer paper.

Generally, in an electrostatic recording device, an electrostatic latent image is formed on the surface of a drum-shaped or belt-shaped electrophotographic photoreceptor or dielectric material, and this electrostatic latent image is dry-developed to form a toner image. shall be. The toner image on the toner image carrier is transferred and fixed onto the transfer material,
There are cases in which the toner image is directly transferred and fixed from the toner image carrier to a transfer material, and cases in which the toner image on the toner image carrier is transferred onto an endless belt-shaped or roller-shaped intermediate transfer member, and the toner image is transferred onto this intermediate transfer member. There are cases where the toner image is further transferred onto the transfer material and fixed at the same time.

The present invention relates to a transfer-fixing device that performs such transfer and fixing at the same time.As a prior art, there is a transfer-fixing method described in Japanese Patent Publication No. 46-41679.
There are various strict conditions in order to transfer and fix the toner image on the toner image carrier or intermediate transfer member to the transfer material at the same time, and it is quite difficult to achieve good transfer and fixation of the toner image. Have difficulty.

Conventionally, as described in Japanese Patent Publication No. 46-41679, for example, a transfer material is heated without heating the toner of the toner image on the intermediate transfer member, and the toner image is transferred by the heat of the transfer material. There are known means for fixing it.

This method is preferable in that there is no risk of overheating the intermediate transfer member and can prevent adverse thermal effects on the toner image bearing member, but it has a low heat utilization rate and is difficult to use for transfer materials made of ordinary paper. It is necessary to add a considerable amount of thermal energy. Moreover, the amount of thermal energy that should be applied to the transfer material usually differs depending on the type of transfer material made of paper. For example, transfer materials made of heavy paper or porous paper require a large amount of heat energy. If the same amount of thermal energy is applied to a transfer material made of paper with a small weight or thickness, it will become overheated.
The transfer material may become deformed or burnt, and in order to achieve good transfer fixation,
It is necessary to adjust the supplied thermal energy depending on the type of transfer material. Furthermore, when transferring and fixing toner images at high speed, it is necessary to apply even more thermal energy to the transfer material, and as a result,
Energy consumption increases, and if the transfer material is not conveyed smoothly and jams occur, there is a great risk of fire.

In the conventional technology in which a transfer material such as transfer paper is pressed against a toner image carrier by a heating roller, the transfer paper is heated by the heat of the heating roller, the toner image is further heated and melted, and the toner is transferred and fixed onto the transfer material. . In this method, the transfer material must be heated to a temperature higher than the toner melting temperature within the nip formed by the pressure contact between the heating roller and the toner image carrier, which is extremely inefficient. It is also necessary to raise the temperature of the heating roller considerably. Furthermore, as the surface movement speed of the carrier increases, the time it takes to pass through the nip area becomes shorter.
The transfer material and toner are not heated sufficiently, making it unsuitable for high-speed processing. In addition, since the temperature setting of the heating roller needs to be high, it is necessary to
Another drawback is that the time it takes for the heating roller to reach the set temperature, the so-called warming-up time, is longer than when it is turned on. Furthermore, in order for the interface temperature between the toner and the transfer material to be equal to or higher than the melting point of the toner, the toner image carrier, such as an electrophotographic photoreceptor, must also be at a temperature higher than the melting point of the toner. This exposes the electrophotographic photoreceptor to high temperatures, which significantly deteriorates the characteristics of the photoreceptor.

SUMMARY OF THE INVENTION An object of the present invention is to provide a transfer fixing device that does not particularly require a preliminary heater to heat the transfer material, has good thermal efficiency, and is capable of sufficient fixing even at high speeds. The above purpose is to provide an image carrier that carries a powder image on its surface, and a pressure roller that has a built-in heating source and is in contact with the image carrier. This is achieved by a transfer and fixing device characterized in that the recording medium is fed between the body and the pressure roller, and the powder image on the image carrier is transferred and fixed onto the recording medium.

The effects of the present invention are as follows.

(1) A heater for heating the recording medium (transfer paper) is unnecessary, and the device can be made small and inexpensive.

(2) Since the temperature setting of the heating roller can be lowered, there is no fear that the recording medium will catch fire and is safe. Also, the warming-up time is shortened.

(3) It is possible to perform sufficient transfer and fixing even if the line speed increases.

(4) The toner image can be fixed even if the temperature of the carrier is low. If the toner image carrier is an electrophotographic photoreceptor, it has the advantage that there is little thermal influence on the photoreceptor.

The present invention, which has the above effects, will be explained in detail by way of examples.

FIG. 1 is a schematic diagram showing an embodiment of an electrophotographic copying machine using an intermediate transfer member. The electrophotographic photoreceptor 1 stretched over the circumferential surface of the drum rotates clockwise, and the surface of the photoreceptor 1 is uniformly charged by a charger 2 provided around the drum, and then an exposure device 3
An original image is projected onto the surface of the photoreceptor 1 to form an electrostatic latent image. The electrostatic latent image on the photoreceptor 1 is developed by a developing device 4 into a toner image.

The toner image on the photoreceptor 1 is then pressed and transferred onto an intermediate transfer member 5, which is an endless belt that rotates in synchronization with the toner image. On the other hand, the recording paper P is sent out by a paper feed roller 6 and is fed between a heating roller 7 and a guide member 8.

FIG. 2 is a detailed diagram of this transfer fixing section. The heating roller 7 is at least connected to the intermediate transfer body 5 during transfer.
A metal roller made of aluminum, stainless steel, iron, or the like with a thin rubber coating is preferable, and has a heater 9 inside for heating.

The guide member 8 is made of, for example, a heat-resistant resin such as a Teflon (trademark) sheet or a Kapton (trademark) sheet,
It is constructed of a metal plate such as aluminum or iron, and the outside is covered with a heat insulating material as required, and the surface that comes into contact with the heating roller 7 has been subjected to a releasable surface treatment. The heating roller 7 and the guide member 8 may be in a non-contact state with a slight gap, or may be in contact with the guide member 8 with some elasticity. Second
In the embodiment shown in the figure, pressing members 10 are provided at both ends of the guide member 8, and the elastic guide member 8 is stretched between them so as to be in contact with the heating roller 7.

Since the frictional force between the heating roller 7 and the recording paper P is much larger than the frictional force between the guide member 8 and the recording paper P, the recording paper P sent out by the paper feed roller 6 is connected to the rotating heating roller 7 and the fixed guide. It is sandwiched between the heating roller 7 and the member 8 and is conveyed as the heating roller 7 rotates. During this time, the recording paper P is heated by the heating roller 7.

The heated recording paper P is further heated by the heating roller 7 in the transfer fixing section where the intermediate transfer body 5 and the heating roller 7 are in pressure contact with each other, and the interface temperature between the toner on the intermediate transfer body 5 and the recording paper P increases. Since the toner image has reached the melting point or higher of the toner, the toner image is transferred and fixed onto the recording paper P. As explained above, the recording paper P
Since the image is heated by the heating roller 7 and reaches the transfer/fixing section where transfer and fixation is performed, the above-mentioned effects of the invention can be obtained.

In the above embodiment, in order to perform the transfer and fixing more completely, the heater 1 is also installed on the holding roller 11 of the intermediate transfer member 5 in the portion that comes into pressure contact with the heating roller 7.
It is effective to incorporate the intermediate transfer member 2 and keep the temperature of the intermediate transfer member 5 close to the toner melting point.

FIG. 3 shows a second embodiment, in which the intermediate transfer body 5 in the first embodiment, which was an endless belt, is changed to a roller-shaped intermediate transfer body 5A to simplify the device. be.

FIG. 4 is an embodiment of FIG. 3, in which the toner image on the photoreceptor 1 is directly transferred and fixed onto the recording paper P without using an intermediate transfer member. In this embodiment, the device can be further simplified. However, the photoreceptor 1 used in this embodiment needs to be resistant to temporary or permanent change in performance due to heat, and is preferably made of amorphous silicon, for example. It is also possible to use a dielectric material instead of the photoreceptor 1, form an electrostatic latent image on the dielectric material by ion control, etc., and directly transfer and fix the image as in the embodiment shown in FIG.

In the third embodiment, the diameter of the heating roller 7 is 50 mmφ, the surface temperature of the heating roller 7 is 140°C,
The line speed was 180 mm/sec, and the length of contact between the recording paper P and the heating roller 7 via the guide member 8 was 50 mm. Under these conditions, the temperature at which 55 kg paper and 70 kg paper were heated up to the transfer fixing section was measured, and both reached a surface temperature of approximately 100° C. at the transfer fixing section. As a result, even if the toner on the image carrier 1 is not in a molten state, within the nip range where the heating roller 7 and the image carrier 1 are in pressure contact, the interface temperature between the toner and the transfer paper P is higher than the melting point of the toner. It was recognized that this could be achieved.

FIG. 5 shows another embodiment of the guide member 8. In contrast to the first embodiment, where the guide member 8 is fixed, the guide member 8 shown in FIG.
1 has a structure in which it moves following the heating roller 7. That is, the belt 81 is stretched between the guide member 8 and the two rollers 82a and 82b, and the guide member 8 is pressed against the heating roller 7. The belt 81 is made of Teflon (trademark) sheet or silicone rubber. The recording paper P is conveyed and heated while being held between the heating roller 7 and the belt 81, and reaches the transfer fixing section.The conveyance and heating of the recording paper P tends to be better. be. Further, a plurality of guide members may be tape-shaped and stretched in the axial direction of the heating roller along the outer peripheral surface of the roller.

[Brief explanation of drawings]

1, 3, and 4 show schematic diagrams of an electrostatic recording device showing an embodiment of the present invention, and FIGS.
The figure is a sectional view showing the relationship between the heating roller and the guide member according to the present invention. DESCRIPTION OF SYMBOLS 1...Photoreceptor, 4...Developer, 5...Intermediate transfer body, 6...Paper feed roller, 7...Heating roller, 8...
...Guide member, 9, 12... Heater, P... Recording paper.

Claims (1)

[Claims] 1. An image carrier carrying a powder image on its surface, a pressure roller that has a built-in heating source and is in contact with the image carrier, and a pressure roller that is in contact with the pressure roller so that the recording material to be fed is aligned with the circumferential surface of the roller to a pressure bonding position. The recording medium is fed between the image carrier and the pressure roller while being heated by the heat from the pressure roller, and the powder image on the image carrier is transferred and fixed to the recording medium. A transfer fixing device characterized by: